Swivel bearing and a steering axle equipped therewith

ABSTRACT

The invention relates to a swivel bearing that is characterized by at least one elastic, radially prestressed bearing element ( 5 ), which closely encircles a rotation axis ( 14 ) completely or at least in areas, is inserted into a bearing opening ( 17 ) of a first bearing part ( 3, 10 ), preferably pressed therein, and which is axially tensioned against at least one face of a second bearing part ( 2, 10 ) by means of a screw connection ( 6 ) acting coaxial to the rotation axis ( 14 ). The invention also relates to a steering axle that is equipped with a swivel bearing of the aforementioned type.

The invention relates to a swivel bearing, which is especially suitable for use in steering axles, in particular trailing steering axles for motor vehicles, such as towing vehicles, trailers, semi-trailers or the like, and in particular meet all desired functions of damping and stabilization at low technical weight and cost expenditures and also can ensure the requisite reset forces in durably reliable manner.

For this purpose the invented swivel bearing is for example essentially distinguished thereby that at least one elastic radially prestressed bearing element, closely encompassing entirely or at least locally a pivot axle, is provided, which [bearing element] is set, preferably forced, into a bearing opening of a first bearing part, and by means of a bolt connection acting coaxially to the pivot axle is clamped axially against at least one abutting face of a second bearing part. By disposing and implementing the elastic bearing element, the desired damping, stabilization and resetting properties can be reliably ensured.

Of advantage is herein if the bearing element is developed as a bushing.

For the sake of simplicity the pivot axle can be formed by a threaded bolt of the bolt connection itself.

To attain the desired functions, it is further proposed that the bearing element comprises a rubber-metal combination or consists of one such.

In a special implementation the bearing element can comprise a tubular inner sleeve of metal, preferably of steel, on the outer surface of which an elastic material, for example rubber, is applied, which is entirely or at least partially encompassed by an outer sleeve.

The outer sleeve can in particular be developed as a thin-walled steel tube and be forced on with high prestress onto the elastic material, such that it [the elastic material] receives the requisite radial prestress. The outer sleeve in this case can in so far also be omitted since it is not required as a bearing face and the prestress of the elastic material cannot be generated in other ways, for example by forcing the bearing element into the bearing opening.

The prestressed elastic material can extend as an integral sleeve over substantially the entire length of the outer surface of the inner sleeve. But it is also of advantage if thereby further functions can be attained, to have the prestressed elastic material extend as separate sleeves only over the two end regions of the outer surface of the inner sleeve.

The sleeves can be formed by one or several rings, for example O-rings.

In order to secure the elastic material such that it is axially nondisplaceable on the outer surface of the inner sleeve, a further implementation of the invention can provide that in any case the radially prestressed elastic material is received over a portion of its thickness in one or several circumferential groove(s) of the outer surface of the inner sleeve and projects over the adjacent region of the outer surface of the inner sleeve.

In order to delimit the axial excursion of the elastic material outwardly, the ends of the outer sleeve can further be bent inwardly.

In the longitudinal region between the two sleeves provided in the end regions of the inner sleeve of prestressed elastic material, preferably between the outer surface of the inner sleeve and the inner surface of the outer sleeve, in a further advantageous implementation of the inventive concept at least one permanently lubricated slide bearing or a roller bearing (needle bearing) is provided. Through the combination of slide bearing or roller bearing, respectively with the elastic material, not only the desired damping and stabilization properties are attained, but the radial loading occurring can also be absorbed without the swivel bearing elastically yielding radially.

There is also the possibility that one sleeve of prestressed elastic material are provided on one half of the outer surface of the inner sleeve and on the other half a slide bearing or roller bearing (needle bearing) between outer surface of the inner sleeve and inner surface of the outer sleeve.

This implementation can be equipped with a relubrication device for the roller bearing.

At the end, associated with the roller bearing, of the bearing element therein a sealing, preferably a radial shaft sealing, can be provided in order to close off the roller bearing toward the outside.

For this case it is also useful to develop said sealing such that it opens under internal pressure; thus, on the one hand, during the relubrication the lubricant can specifically exude at this site and, on the other hand, no dirt can penetrate into the bearing arrangement.

In all previously discussed embodiments of the swivel bearing, it is of advantage if the elastic material is radially prestressed such that the provided swivel angle between the two bearing parts is attained through its elasticity alone and, when the torsion forces are removed, they automatically return into their starting position. Such an embodiment is especially suitable for use in steering axles.

It can moreover be provided that only after exceeding a specified swivel angle the elastic material slips through on the inside with respect to the inner sleeve or on the outside with respect to the outer sleeve. For this purpose the elastic material can be secured with the inner sleeve and/or the outer sleeve through adhesion, vulcanization and/or form fit against slipping through.

The invention also relates to a steering axle, in particular trailing steering axles, for motor vehicles such as towing vehicles, trailers, semi-trailers or the like, at whose axle beam the wheels are articulated by means of steering forks connected with one another with a tie rod, with a swivel bearing provided between the axle beam and the wheels or the steering forks and the tie rod, respectively.

Such steering axles are known per se (cf. DE 19 45 589 A1, DE 44 05 325 C1 and DE 197 16 150 A1). The stabilization systems provided are intended to prevent shimmy movements of the wheels when driving in a straight line, steer through a fish-tail effect, dampen the steering movement during curve driving and support the back-steering force. The functions “stabilizing” and “damping” are fulfilled in known trailing steering axles only with considerable technical complexity: The damping of deflection or steering movements takes place virtually exclusively via hydraulic steering dampers or gas pressurized dampers, which most often are secured, on the one hand, on the axle beam and, on the other hand, on the tie rod and, consequently, during the steering movements are retracted and extended. For the stabilization, i.e. avoidance of shimmy movements of the steered wheels when driving straight, up to this time further mechanical complexity had been required, such as for example stabilization devices pressurized with compressed air, such as are disclosed inter alia in DE 1 945 589 A1 and DE 73 38 796 U, or for example purely mechanical devices according to DE 44 05 325 C1 and DE 197 16 150 A1. While such damping and stabilization systems in general meet the requirements made of general driving practice, however, due to the high technical complexity, they can exhibit distinctive features, which become apparent for example during a steering-in of the axle, taking place too late or not at all, with light and unloaded motor vehicles or in undesirable swerving of the rear end of the vehicle with full loading and especially short motor vehicles on curvy roads and under hard driving habits.

Steering axles, in particular motor vehicle front axles or force-steered axles in semitrailers, must allow steering without great resistance. For this purpose, occasionally great technical complexity is exercised up to needle-bearing support steering bolts. In the case of trailing steering axles of past design engineering, ease of steering movement is also attained by way of complexity of bearing bushings, which run on hardened steering swivel bolts. Since steering movements on trailing steering axles can only be effected due to transverse forces in connection with at least one rigid leading axle, and guiding steering linkage, etc. are not available, these must be made again quasi “controlled stiffly” with the aid of considerable additional complexity, namely with damping and stabilization devices, in order to fulfill the described functions.

The aim of the present invention is therefore also to propose a steering axle, while avoiding the disadvantages described in conjunction with prior art, which, with low technical, weight and cost expenditures, fulfills durably and reliably all functions of damping and stabilizing required at such steering axle.

This problem is solved with a steering axle of the previously cited type according to the invention for example essentially thereby that the swivel bearing is such of the previously described type, the axle beam and the steering forks or the tie rod and the steering forks, respectively, forming in each instance the first or second bearing part, respectively.

With such a stabilization and damping system good and secure driving behavior is attained with low fabrication and cost expenditures.

The swivel bearing between steering forks and tie rod assists through its damping the stabilization through the swivel bearing between axle beam and steering forks. The sum of all spring rates involved in the torsion lead to the desired back-steering effect.

Further generation of the inventive concept determining the steering axle provides that, between an abutting face of the axle fist of the axle beam and a staying face of a recess of the bearing fork, receiving the axle fist, a pair of undulated washers retained to one another with undulated contact faces facing one another under axial stress is disposed, one undulated washer being connected torsion-tight with the axle fist and the other undulated washer torsion-tight with the steering fork and, when driving straight, the two undulated washers, preferably over the entire surface or substantially over the entire surface, are in contact on one another and form a latching position and when torsioning the undulated washers against one another, locally gaps are formed between them and the areal regions in contact on one another of the undulated contact faces decreases with increasing steering angle.

In the latching position of the undulated washers during fast straight driving in this way shimmy movements of the wheels, which can occur through weight imbalancing and/or street unevenness, are prevented. During the steering process both undulated washers torsioning against one another such that the tangential regions of the contact faces increase or decrease in size depending on the steering angle. With increasing steering angle the motor vehicle is raised according to the oblique planes of the undulated washers and simultaneously the elastic material is deformed in the at least one bearing elements. Through the spring rates of the elastic material an assistance of the back-steering force occurs, which is greater the greater the steering angle. The use of undulated washers is known per se (cf. DE 36 16 998 A1). However, [in this patent] the intent is only to utilize the undulated washers as pressure washers in connection with one helical spring each for stabilizing the straight-ahead driving. However, no steering angle-dependent back-steering force occurs in that case and the conventional complexity of bushing-supported and hardened steering swivel bolts is absolutely required.

Further goals, characteristics, advantages and application feasibilities of the invention are evident in the following description of embodiment examples in conjunction with the drawing. All described and/or graphically represented characteristics by themselves or in any combination form the subject matter of the invention, even independently of their summary in individual claims or their reference back. In the drawing depict:

FIG. 1 a trailing steering axle comprising the invention with radius arm for air suspension in top view during straight driving,

FIG. 2 the trailing steering axle according to FIG. 1 in top view with the wheels steered in,

FIG. 3 a vertical section through a steering fork bearing arrangement and tie rod bearing arrangement,

FIG. 3A top view onto the configuration according to FIG. 3,

FIG. 4A an undulated washer pair according to the invention in straight-driving position,

FIG. 4B the undulated washer pair according to FIG. 4A in the state of the steered-in wheels, as well as

FIGS. 5 and 6 two further embodiments of a swivel bearing according to the invention.

The invention will first be explained in further detail by example of a first embodiment of a swivel bearing 1 according to the invention utilized in a trailing steering axle of a motor vehicle.

The steering axle depicted in FIGS. 1 and 2 and developed as a trailing steering axle has an axle beam 2 disposed on two radius arms 12, disposed at a spacing from one another, articulated at their particular front end on the motor vehicle chassis, for example formed of metal plate and having at their rear end holes, for example for receiving air spring elements, [and disposed on radius arms 12] for example tightly clamped or welded, as the stationary bearing part, at whose outer ends, cranked in the driving direction, one steering fork 10 each is articulated as the moving bearing part. The radius arm 12 can also be replaced by conventional spring guides or leaf springs. The pivot axle 14, formed by the threaded bolt of a bolt connection 6, of the swivel bearing are located at distance A in the driving direction in front of the axle center. A tie rod 3 ensures the tracking fidelity of the wheels 4, in that the ends of the steering fork 10 opposite to the wheels 4 are connected via swivel bearing 1 with the outer end of the tie rod 3. The trailing steering axle has no mechanical steering transmissions such as rod arrangements, cable linkages, hydraulic cylinders, etc. The steering action takes exclusively place via the side forces K between tires and street occurring during curve driving. They must therefore run jointly with at least one rigid leading axle, which can be disposed in front of it or behind.

In FIGS. 3 and 3A is illustrated the functional principle of the steering axle according to the invention and the swivel bearing 1 set between axle beam 2 and steering fork 10. Instead of otherwise conventional hardened steering swivel bolts, which are bushing or needle supported, in the particular swivel bearing 1 between axle beam 2 and steering fork 10 for the development of a swivel bearing 1 serving for stabilization and damping, elastic bearing elements 5 encompassing the particular pivot axle 14 of the swivel bearing 1 are provided and specifically in the depicted embodiment example within bearing openings 17 of the steering fork 10 above and beneath the axle fist 9 of the axle beam 2 penetrated by the pivot axle 14. The bearing elements 5 comprise a tubular rigid inner sleeve 7, preferably comprised of steel, which on its outer circumferential surface bears an elastic material 22, such as a rubber mixture, applied as a bushing. The elastic material 22 is encompassed by an outer sleeve 21 of a thin-walled steel tube, which is forced with high prestress onto the shell of elastic material 22 in order to attain high loading capacity.

In order for the elastic material 22, on the one hand, not to swell out at the ends at a high radial loading, but, on the other hand, a material layer to be available of sufficient thickness and elasticity for the degree of deformation occurring during driving operation, in the depicted embodiment example the ends of the inner sleeve 7 are thickened toward the inside, in that for example a thick-walled tube with the exception of the ends is turned narrower with the formation of a circumferential groove 25. For this purpose the ends of the outer sleeve 21 can also be bent inwardly, in order to enclose the elastic material 22 also at the abutting side.

The bearing elements 5 are each pressed into their bearing openings 17. The inner sleeves 7 of the bearing elements 5 are clamped axially against an abutting face 8 of the axle fist 9 by means of a bolt connection 6, which penetrates with a threaded bolt forming the pivot axle 14 the bearing openings 17 of the steering fork 10 as well as also the axle fist 9 of the axle beam 2. The bushing-like bearing element 5, which is formed of the described rubber-metal combination, is adaptingly received on the threaded bolt of the bolt connection 6 forming the pivot axle 14. In this way the bearing elements 5 fulfill the functions of the articulated bearing arrangement between stationary axle beam 2 and movable steering fork 10 as well as also of the damping of the steering movement as well as the assistance of the back-steering force and therewith the stabilization. Consequently it forms a significant component of a swivel bearing 1, which can also be utilized otherwise with advantage, thus not only on a steering axle of a motor vehicle.

The stationary axle fist 9 is received in a recess 19 of the movable steering fork 10. Between the lower abutting face 8 of the axle fist 9 and a staying face 20, opposite to it, of the recess 19 in a special embodiment of the swivel bearing 1 a pair of undulated washers 11, 11 a can be positioned in order to form a back-steering device. The lower undulated washer 11 a is secured torsion-tight on the steering fork 10 via at least one securement element 13. The upper undulated washer 11 is positioned between the inner sleeve 7 of the lower bearing element 5 and the lower abutting face 8 of the axle fist 9 and is secured torsion-tight on the axle fist 9.

As is especially evident in FIGS. 4A and 4B, the undulated washers 11, 11 a have undulated contact faces 15, 15 a facing one another, which in the straight-ahead driving are in contact on one another over a maximum area and form a latching position. The latching position prevents during fast straight-ahead driving shimmy movements of the wheels, which can occur due to weight imbalancing and/or unevenness of the road. During the steering process the undulated washers 11, 11 a turn against one another, such that locally gaps 16 are formed and the areal region, in which the undulated contact faces 15, 15 a are in contact on one another decreases with increasing steering angle. In this way with increasing steering angle the motor vehicle is raised according to the cooperating inclined surfaces of the undulated contact faces 15, 15 a and simultaneously the elastic bearing element 5 is deformed. Through the spring rate of the bearing elements 5 a back-steering assistance is generated, which is greater the greater the steering angle. The particular undulation peaks of the undulated washers 11, 11 a with the formation of radial grooves 23, 23 a are developed to receive lubricant. The grooves 23, 23 a can also absorb possibly occurring abrasions of the undulated contact faces 15; 15 a. Furthermore, the undulated contact faces 15, 15 a can be protected through (not shown) elastic sealing collars against external dirt effects and/or splashed water. Both measures serve to increase the service life.

In the depicted embodiment example the particular steering connections of the tie rod ends 18 with the steering fork 10 are developed as swivel bearing 1′ according to the invention with damping and stabilization properties. For this purpose at least one elastic bearing element 5′ encompassing the associated pivot axle 14′ of swivel bearing 1′ is provided, which is set into, preferably pressed into, a bearing opening 17′ of the steering fork 10 and by means of a bolt connection 6′ coaxial with the pivot axle 14′, whose threaded bolt forms the pivot axle 14′, is clamped radially against the inner surface of the bearing opening 17′ and axially against staying faces 20′ opposing one another a recess 19′ of the steering fork 10. The bearing element 5′ comprises an inner sleeve 7′, into which is fitted the threaded bolt of the bolt connection 6′. The bearing element 5′ developed like a bushing is formed like the bearing element 5 of a rubber metal combination, in that onto the inner sleeve 7′ an elastic material 22′ is applied and on the latter a thin-walled outer sleeve 21′ of steel is pressed. This swivel bearing 1′ assists as damping device the effect of the stabilization provided in the swivel bearing 1 between axle beam 2 and steering fork 10. Independent of the embodiment of the tie rod bearing arrangement, the sum of all spring rates involved in the torsion leads to the desired back-steering effect.

In FIGS. 5 and 6 two additional embodiments of a swivel bearing 1 according to the invention is depicted, which preferably could be used in steering axles of the previously described type, but are generally applicable as a structural element.

In the maintenance-free swivel bearing 1 according to FIG. 5, the bearing element 5 is closed at both ends via radially prestressed elastic sleeves 22, 22 b, 22 c. The elastic sleeves 22 b, 22 c can be comprised of one or several individual elements, for example large-volume O-rings 22 c. Between the two radially prestressed elastic elements 22, 22 b, 22 c a permanently lubricated slide bearing 26 is disposed in the interspace between the outer face of the inner sleeve 7 and the inner surface of the outer sleeve 21.

The force attack F in the direction of radial loading is depicted centrally [with respect] to the swivel bearing 1.

In the variant of a swivel bearing 1 according to the invention depicted in FIG. 6, is provided adjacent to a radial bearing 27, developed as roller bearing, on the outer surface of the inner sleeve 7 only at one side a radially prestressed elastic element 22, 22 b and on the other end a sealing 28, for example a commercially available radial shaft sealing ring. This embodiment can be equipped with a relubrication device 29, the sealing 28 usefully being developed as a sealing ring opening toward the outside under internal pressure, such that, on the one hand, during relubrication the lubricant can exude specifically at this site and, on the other hand, no dirt penetrates into the bearing arrangement. In place of the depicted roller bearing 28, here also a slide bearing 26 can be used.

The elastic elements 22, 22 a to 22 d are prestressed in all variants such that the particular swivel angle provided for the application purpose is attained through its elasticity alone without a sliding movement between the elastic material and the inner sleeve 7 or the outer sleeve 21 taking place and that through this property the swivel bearing 1 is reset automatically into its starting position when the torsion forces are removed. This can structurally also be implemented such that only after a swivel angle is exceeded the elastic element 22, 22 a to 22 b slips through on the inside or the outside such that it does not tear off on the inside, but in this case with the consequence that the pivoting parts no longer spring back completely into the starting position. In order to avoid the premature slipping-through, the elastic material can additionally be connected either with the inner sleeve or with the outer sleeve fixedly or via form fit (for example via toothings or via holes in the metal parts) through adhesion or vulcanization.

In the variants depicted in FIGS. 5 and 6, which can be applied instead of the swivel bearings 1, 1′ in FIGS. 1 to 3A, the combination of a radial bearing with an elastically resilient material is essential, which fulfills the function of being radially loadable without radially yielding elastically and the two pivoting parts (for example fist and fork) being swivellable in time up to the swivel angle provided in each instance for the application purpose and, when the swivel force is removed, the articulation parts spring back into the starting position. An intended nondestructive slipping-through is therein advantageous after a specific swivel angle has been exceeded.

LIST OF REFERENCE SYMBOLS

-   1, 1′ Stabilization and swivel bearing (as part of a damping device) -   2 Bearing part (axle beam) -   3 Bearing part (tie rod) -   4 Wheels -   5, 5′ Bearing elements -   6, 6′ Bolt connections -   7, 7′ Inner sleeves -   8 Abutting face -   9 Axle fist -   10 Bearing part (steering forks) -   11, 11 a Undulated washers -   12 Radius arm -   13 Securement element -   14, 14′ Pivot axles -   15, 15 a undulated contact faces -   16 Gap -   17, 17′ Bearing openings -   18 Tie rod ends -   19, 19′ Recesses -   20, 20′ Staying faces -   21, 21′ Outer sleeves -   22, 22′ Elastic material -   22 a, 22 a′ -   22 b, 22 c -   22 d Sleeves or rings -   23, 23′ Grooves -   24 Holes -   25 Circumferential grooves -   26 Slide bearing -   27 Roller bearing -   28 Sealing (radial shaft sealing) -   29 Relubrication device -   A Distance -   F Force attack -   K Side forces 

1-21. (canceled)
 22. Swivel bearing, wherein at least one elastic radially prestressed bearing element (5) entirely or at least locally closely encompassing a pivot axle (14), which set into, preferably pressed into, a bearing opening (17) of a first bearing part (3, 10) and, by means of a bolt connection (6) coaxially acting with respect to the pivot axle (14) is clamped axially against at least one abutting face of a second bearing part (2, 10).
 23. Swivel bearing as claimed in claim 22, wherein the bearing element (5) is developed as a bushing.
 24. Swivel bearing as claimed in claim 22, wherein that the pivot axle (14) is formed by a threaded bolt of the bolt connection (6).
 25. Swivel bearing as claimed in claim 22, wherein the bearing element (5) comprises a rubber-metal combination or is comprised of such.
 26. Swivel bearing as claimed in claim 22, wherein the bearing element (5) comprises a tubular inner sleeve (7) of metal, preferably of steel, on whose outer surface an elastic material (22), for example rubber, is applied, which is entirely or at least partially encompassed by an outer sleeve (21).
 27. Swivel bearing as claimed in claim 26, wherein the outer sleeve (21) is developed as a thin-walled steel tube and is forced onto the elastic material (22) under high prestress.
 28. Swivel bearing as claimed in claim 26, wherein the prestressed elastic material (22) extends as an integral sleeve (22 a) over substantially the entire length of the outer surface of the inner sleeve (7).
 29. Swivel bearing as claimed in claim 26, wherein the prestressed elastic material (22) extends as separate sleeves (22 b) only over the two end regions of the outer surface of the inner sleeve (7).
 30. Swivel bearing as claimed in claim 26, wherein the sleeves (22 a, 22 b) are formed by one or several rings, for example O-rings (22 c).
 31. Swivel bearing as claimed in claim 26, wherein the elastic material (22) in any case over a portion of its thickness is received in one or several circumferential grooves (25) of the outer surface of the inner sleeve (7) and projects beyond the adjacent region of the outer surface of the inner sleeve (7).
 32. Swivel bearing as claimed in claim 27, wherein the ends of the outer sleeve (23) [sic: 21] are bent inwardly.
 33. Swivel bearing as claimed in claim 29, wherein between the two sleeves (22 b), provided in the end regions of the inner sleeve (7), of prestressed elastic material (22), between the outer surface of the inner sleeve (7) and the inner surface of the outer sleeve (23) [sic: 21] are provided at least one permanently lubricated slide bearing (26) or a roller bearing (needle bearing) (27).
 34. Swivel bearing as claimed in claim 25, wherein a sleeve (22 d) of a prestressed elastic material (22) is provided only on one half of the outer surface of the inner sleeve (7) and on the other half is provided a slide bearing (26) or a roller bearing (needle bearing) (27) between the outer surface of the inner sleeve (7) and the inner surface of the outer sleeve (23) [sic: 21].
 35. Swivel bearing as claimed in claim 33, wherein a relubrication device (29) for the roller bearing (27).
 36. Swivel bearing as claimed in claim 33, wherein the roller bearing (27) is closed toward the outside by a sealing (28), for example a radial shaft sealing.
 37. Swivel bearing as claimed in claim 36, wherein the sealing (28) is developed as a sealing opening toward the outside under internal pressure.
 38. Swivel bearing as claimed in claim 22, wherein the elastic material (22) is radially prestressed such that the provided swivel angle between the two bearing parts (9, 10) is attained through its elasticity alone and, when the torsion forces are removed, these return automatically into their starting position.
 39. Swivel bearing as claimed in claim 38, wherein first, after exceeding a specified swivel angle, the elastic material (22) slips through on the inside relative to the inner sleeve (7) or on the outside relative to the outer sleeve (21).
 40. Swivel bearing as claimed in claim 26, wherein the elastic material (22) is secured with the inner sleeve (7) and/or outer sleeve (21) by adhesion, vulcanization and/or form fit against slipping through.
 41. Steering axle, in particular trailing steering axle, for motor vehicles, such as towing vehicles, trailers, semitrailers, or the like, on whose axle beam (2) the wheels (4) are articulated by steering forks (10) connected with one another by means of a tie rod (3), with a swivel bearing (1) provided between the axle beam (2) and the wheels (4) or the steering forks (10) and the tie rod (3), wherein the swivel bearing (1) is one such as claimed in claim 22 in which the axle beam (2) and the steering forks (10) or the tie rod (3) and the steering forks (10) form the fist or the second bearing part (9, 10) respectively.
 42. Steering axle as claimed in claim 41, wherein between an abutting face (8) of the axle fist (9) of the axle beam (2) and a staying face (20) of a recess (19) receiving the axle fist (9) of the steering forks (10) a pair of undulated washers (11, 11 a) held on one another under axial stress with undulated contact faces (15, 15 a) facing one another, is disposed, where the one undulated washer (11 a) [sic: (11)] is torsion-tight connected with the axle fist (9) and the other undulated washer (11 a) torsion-tight with the steering fork (10), and during straight-ahead driving the two undulated washers (11, 11 a) are in contact on one another preferably over the entire surface or substantially over the entire surface, and form a latching position and, upon the torsion of the undulated washers (11, 11 a), locally between them gaps (16) are formed, the areal regions of the undulated contact faces (15, 15 a) being in contact with one another decrease with increasing steering angle. 